Clostridium difficile is a spore-forming anaerobic and toxin-producing bacillus. It is the most common cause of nosocomial antibiotic-associated diarrhea. A CDC study estimated that 29,000 deaths were caused by Clostridium difficile in the U.S. in 2011. Antibiotic treatment of Clostridium difficile infections may be difficult, due both to antibiotic resistance and physiological factors of the bacteria (e.g., spore formation and protective effects of the pseudomembrane). Accordingly, there exists a need for effective therapies and prevention of infections caused by Clostridium difficile. 